In recent years, foil balloons have grown in popularity for festive occasions in comparison with traditional latex balloons. Foil balloons, unlike latex balloons, may be manufactured with a decorative, metallized finish, and are readily printed during manufacture with colorful graphics using conventional methods such as flexography or silkscreen. Foil balloons of various designs are currently available at most greeting card stores.
The greeting card industry has shown a strong trend as of late toward customization. Thus, for example, many greeting card stores feature equipment that allows patrons to produce customized greeting cards on the premises. This interest has extended to other items sold by the industry, including decorative foil balloons. However, flexography, silk screen, and the other printing techniques commonly used by the industry to produce decorative foil balloons are generally limited to large scale production, and do not lend themselves to small scale, customized production of the type required for customized or personalized items.
Some attempts have been made to develop methods for the production of customized foil balloons. Thus, for example, PCT Intl. Pub. No. WO 00/11067 (Lang) discloses methods for producing decorative foil balloons through the use of a conventional ink jet printer. In accordance with the methodology disclosed therein, the surface of the foil is first adapted for printing by having a surface coating applied thereto. The balloon is then fed through a conventional inkjet printer which is set up to print a design on the adapted surface of the foil.
However, the approach of WO 00/11067 (Lang) suffers from a number of serious drawbacks. For example, foil balloons are typically constructed from very thin caliper foils so that they will be suitably buoyant, and hence tend to have very little rigidity. Consequently, when a foil balloon is fed through a conventional inkjet printer, it tends to wrap around the drums, rollers and other feeding mechanisms of the printer, thereby causing the printer to jam.
WO 00/11067 (Lang) also notes that the balloon may be wrapped around, or adhered to, a rigid substrate such as card sheet to facilitate printing. However, this approach suffers from the drawback that such a substrate tends to jam the feeding mechanisms of conventional printers, which are designed for feeding paper sheets of ordinary caliper. The approach of WO 00/11067 (Lang) also assumes that the uninflated balloon can be pressed into a flat or smooth surface suitable for printing, and thus places limitations on the size and geometry of the balloon and on the way that the balloon is compressed for storage or shipping. Moreover, the approach of WO 00/11067 (Lang) is not applicable to inflated balloons.
Transfer ink jet printing methods are well known and involve printing onto a temporary carrier sheet from which the image is subsequently transferred, by lamination, to the final substrate. Transfer printing systems are described, for example, in U.S. Pat. No. 5,501,902 (Kronzer), U.S. Pat. No. 5,798,179 (Kronzer), U.S. Pat. No. 6,113,725 (Kronzer), and U.S. Pat. No. 6,200,668 (Kronzer). In such a system, an ink jet receptive layer may be combined with a thermally activated adhesive on a temporary supporting sheet. After imaging, the receptor layer, including the image, is transferred under the influence of heat and pressure to the final substrate. However, the use of a thermally activated adhesive is a requirement of such systems, since the sheet must pass through a printer without adhering to the feed mechanism. Since foil balloons are temperature sensitive and tend to distort and shrivel at elevated temperatures, this requirement precludes the use of this technique for transfer to foil balloons.
Some ink jet transfer printing systems have also been described whereby a thermally activated adhesive is coated on the article that is to receive the final image. A system of this type is described, for example, in U.S. Pat. No. 5,766,398 (Cahill et al.). However, this approach suffers from the infirmities noted above in that the use of a thermally activated adhesive precludes its use on temperature sensitive substrates such as foil balloons.
A room temperature transfer system has been described in U.S. Pat. No. 6,153,038 (Brooker). In accordance with the methodology disclosed therein, an image is first printed on a non-adsorbent medium such as transparency film, as through the use of a conventional inkjet printer. The image is then imparted to the target substrate by bringing the surface bearing the image into contact with the target substrate with the application of pressure. The target substrate may be provided with a material that will adhere to the surface of the substrate and is sufficiently absorbent, porous, or abrasive such that it will properly receive the ink image.
The approach suggested in U.S. Pat. No. 6,153,038 (Brooker) is advantageous in that it does not require the application of heat (only pressure), and can therefore be used to print onto a temperature sensitive substrate. Moreover, the substrate to which the image is to be imparted does not itself have to be passed through the inkjet printer, thus avoiding many of the problems noted above. However, this approach is undesirable in that the printing of the image on the non-adsorbent medium allows the ink to coalesce before the image is imparted to the target substrate, thereby resulting in blurring of the image and an overall reduction in image quality. Moreover, any lateral motion of the non-adsorbent medium during the image application process will cause the image to be smeared. Hence, this approach is not very user friendly and is not suitable where high image quality is desirable.
An alternative method of cold image transfer has been disclosed in U.S. Pat. No. 6,277,229 (Popat et al.) whereby the imageable layer on a transfer sheet comprises a water activated adhesive that is rendered tacky by application of the inkjet ink. Transfer occurs only in those areas that have been activated by the ink. As with other wet transfer techniques, however, this procedure is prone to smudging of the image during the transfer process.
There is thus a need in the art for a method for imparting graphics to foil balloons and to other temperature sensitive substrates and articles, and which can be used in conjunction with conventional inkjet printers. There is also a need in the art for a method for imparting graphics to foil balloons which can be used with balloons having virtually any geometry. These and other needs are met by the present invention, as hereinafter described.